Yesterday I upgraded our modem to the Xfi Advanced Gateway modem and now our phone has no dial tone. The phone is directly plugged into the modem, and the phone worked perfectly before I switched out the modem. When I called Xfinity, they reset the modem and had me disconnect and reconnect all cables but still no luck. I can see incoming calls in call history and retrieve voicemail through the website. Is there anything else I can try at home to fix the problem before I have to wait for a service call?